||BERKELEY, CA — Lawrence
Berkeley National Laboratory (Berkeley Lab) has taken several recent
actions to answer questions involving the use of tritium in Laboratory
research, in cooperation with the Berkeley community and the U.S.
Environmental Protection Agency (EPA).
In order to address local concerns about the potential impacts on public health from radiation produced in scientific investigations, Laboratory Director Charles V. Shank has initiated the following:
The Task Force completed its second meeting on March 1 and is scheduled to meet a third time on April 25 to focus on formulating a comprehensive sampling plan measuring tritium in the environment. This plan will gather data that the EPA can use to evaluate the Laboratory’s eligibility for EPA’s National Priority List. Though all data gathered to date indicates the Laboratory is well within all federal and state public health standards, the EPA has requested additional measurements.
At the first meeting of the task force members in January, Shank told them, "The issue before us is: Is there an imminent health danger in this community (from Laboratory tritium emissions)? We will provide data, conduct real measurements, and get the information for you. We will cooperate with all city and regulatory bodies."
For some time now, certain community representatives and city officials have expressed concern about the very small amounts of tritium that are emitted through research activities at the Lab’s National Tritium Labeling Facility (NTLF). The NTLF conducts biochemical studies to create new radiotracers to analyze biological reactions at the cellular and molecular levels.
The Task Force was formed to engage community stakeholders in the process of tritium sampling and its evaluation so that concerns about public health can be answered. A 1997 Health Risk Assessment conducted by the Laboratory, based on the Lab’s own monitoring, has shown that annual air emissions from the NTLF result in off-site radiation doses that are less than 2 percent of the EPA’s acceptable public health standard.
In response to community concerns, however, the City of Berkeley hired Franke, of the German environmental consulting firm Institut fur Energie und Umweltforschung (IFEU), to do an analysis of all reports and data concerning tritium and radiation exposure. In recent meetings at the Laboratory, Franke conveyed his needs, and Laboratory staff began the process of collecting requested information.
Hoffman, President of SENES Oak Ridge, Inc., Center for Risk Analysis, of Tennessee, brings more than 25 years of experience as an environmental scientist specializing in human dose and risk evaluation for radionuclides and chemicals to his consulting role for the Lab. Hoffman will support Franke’s information requests.
Thomas earned his reputation as a pioneer in the field of radiation safety for particle accelerators. He recently chaired a Joint Task Group of the International Commission on Radiological Protection and the International Commission on Radiation Units and Measurements to produce a definitive report on radiological protection against external radiation.
Thomas worked at Berkeley Lab from 1963 to 1991 and served as Director of the Occupational Health Division, monitoring the operations of the Bevatron, Berkeley’s historic synchrotron whose accomplishments over four decades led the frontier in the fields of high-energy and heavy-ion physics.
Early discoveries at the Bevatron -- or Bevalac, as it was called after its linkage with the SuperHILAC linear accelerator in the 1970s -- resulted in four Nobel prizes. The Bevatron, which operated from 1954 until its decommissioning in 1993, made major contributions to four distinct areas of research: high-energy particle physics, nuclear heavy-ion physics, medical research and therapy, and space-related studies of radiation damage and heavy particles in space.
In accelerators such as this, the energizing of protons results in the emission of radiation in the form of neutrons.
In his analysis of historical radiation doses at Berkeley Lab, Thomas relied on public laboratory reports that showed the maximum potential annual dose off-site reached 820 millirem in 1959 when the maximum federal public safety standard was 1,500 millirem per year. His subsequent recalculations, based on modern conversion methods, have placed that 1959 figure at approximately 360 millirem.
Largely due to added shielding around the Bevatron, maximum potential doses in subsequent years dropped significantly, even as the beam intensities of the accelerator were increasing. The public records show that the annual measured radiation doses continued falling to below 10 millirem. Through the entire period of accelerator operations, maximum potential Laboratory radiation dose levels have always been below the federal safety limits in effect at the time, according to data in the historic published reports. Today’s federal safety standard for radiation from all sources is 100 millirem per year.
In 1999, site-wide, the Laboratory had a total maximum potential dose exposure at its perimeter for radiation from all sources of less than 1 millirem, which is substantially less than the effective dose equivalent received from a dental x-ray (10 millirem).
Thomas’ analysis, and the published reports from which his analysis was drawn, have been forwarded to Franke for his review.
The public is invited to attend the April 25 meeting of the Environmental Sampling Project Task Force, beginning at 6:30 p.m. at the First Congregational Church, 2345 Channing Way in Berkeley. All records of the task force, including transcripts of meetings, can be found on the Environmental Sampling Project Task Force Web site.